Oct 24, 2018 mechanical properties of solids 05 elasticity. Tensile strength is the breaking stress that will cause. Bones are brittle and the elastic region is small and the fracture abrupt. The youngs modulus can be directly obtained from uniaxial tension or compression experiments, and typical values for a few select fluoropolymers at room temperature are presented in table 11. It does refer to all the stress induced strain that is recovered. A configuration is a set containing the positions of all particles of the body. A deformation may be caused by external loads, body forces such as gravity or electromagnetic forces, or changes in temperature, moisture content, or chemical. Elasticity, ability of a deformed material body to return to its original shape and size when the forces causing the deformation are removed. Newest stressstrain questions physics stack exchange. At, we provide access to the bestquality, bestvalue private tutoring service possible, tailored to your course of study. Real rigid bodies are elastic we can slightly change their dimensions by pulling, pushing, twisting or compressing them. The block is placed such that 60x60 comes on the lower and upper surface.
Compressibility of a material is the reciprocal of its bulk modulus of elasticity. Find the shearing stress, shearing strain and shear modulus. Elasticity 1 elasticity physics deformation mechanics. A body with this ability is said to behave or respond elastically. Solid objects will deform when adequate forces are applied to them. Units and dimension of the modulus of elasticity are same as those of stress. Modulus of elasticity an overview sciencedirect topics. For example, a guitar string made of nylon stretches when it is tightened, and the elongation. Unlike bones and tendons, which need to be strong as well as elastic, the arteries and lungs need to be very stretchable. Elasticity is a measure of how much an object deforms strain when a given stress force is applied. For any state of stress, we can find a set of planes on which only normal stresses act and the shearing stresses are zero.
These two quantities are related by the following equation that defines the modulus stress modulus x strain of elasticity. Elasticity 5 as the stress was further increased, a point y, known as the yield point, at which the stress rapidly dropped, was reached. L crosssectional area a 1 f l0 y a proportionality factor youngs modulus f y a. Apr 22, 2019 it is defined as the ratio of tangential stress to the shearing strain, within the elastic limit. It is defined as the ratio of tangential stress to the shearing strain, within the elastic limit. E is a constant because l, a and k are all constant. The theory of elasticity contains equilibrium equations relating to stresses, kinematic equations relating. This twophase morphology is responsible for the viscoelastic mechanical properties, the stressstrain behavior, the tensile. There are three elastic moduli, one for each of the three basic.
Elasticity 1 free download as powerpoint presentation. Elasticity branch of physics that describes how real bodies deform when forces are applied to them. Modulus of elasticity the modulus of elasticity youngs modulus e is a material property, that describes its stiffness and is therefore one of the most important properties of solid materials. This idea was first stated by robert hooke in 1676 as an anagram, then in 1678 in latin, as ut tensio, sic vis, which means. Generalized hookes law stress a stress is a force or combination of forces distributed throughout the whole of an object that acts to deform it stresses take the general form of force divided by area fa.
Apr 21, 2020 elasticity, stress and strain and stressstrain curve, class 11, physics edurev notes is made by best teachers of class 11. The proportionality constant k depends upon a number of factors for the material. To a greater or lesser extent, most solid materials exhibit elastic behaviour, but. Linear elasticity an overview sciencedirect topics. A block of gelatin is 60 mm by 60 mm by 20 mm when unstressed. For metals or springs, the straight line region in which hookes law pertains is much larger.
When the heart is pumping during systole, blood is forced through the heart and the various vessels. This document is highly rated by class 11 students and has been viewed 15976 times. The energy is stored elastically or dissipated plastically. Hookes law states that, within elastic limits, the ratio of stress to the corresponding strain produced is a constant. Stress, strain, youngs modulus problems and solutions. The straight segment is the linear region where hookes law is obeyed. A cord has original length of 100 cm is pulled by a force. Nov 12, 2019 science physics elasticity numerical problems on stress, strain, and youngs modulus in this article, we shall study concept application and numerical problems on longitudinal stress, longitudinal strain, youngs modulus of elasticity. Activityforces, elasticity, stress, strain and youngs modulus handout 2 elasticity and youngs modulus elasticity describes a material property in which the material returns to its original shape after stress has been applied and then removed. It does not imply that the strain be large or that any particular mathematical relationship exists between stress and strain or that all the strain be recovered.
Kariapper kfupm 127 elastic properties of solids we will consider three types of deformations and define an elastic modulus for each. The given figure shows a stressstrain curve of a given metal. What does elasticity with torque and twist depending on normal strain and normal stress look like. Still greater forces permanently deform the object until it finally fractures. Elasticity is a measure of the deformation of an object when a force is applied. Thicker nylon strings and ones made of steel stretch less for the same applied force, implying they have a larger k see figure 2. The engineering normal strain or engineering extensional strain or nominal strain e of a material line element or fiber axially loaded is expressed as the change in length.
Describe with examples the youngs modulus, shear modulus and bulk modulus. Write the pressure as p, the original volume as v and the change in volume as dv. For larger forces, the graph is curved but the deformation is still elastic. Figure shows a stressstrain relationship for a human tendon. Some tendons have a high collagen content so there is relatively little strain, or length change. Fluids and elasticity in this chapter we study macroscopic systems. Note that this stressstrain curve is nonlinear, since the slope of the line changes in different regions. Pdf the present chapter contains the analysis of stress, analysis of strain and stressstrain.
For a given material, youngs modulus e is the ratio of stress to strain, provided the limit of. If the material is elastic, the object will return to its initial shape and size when these forces are removed. The elastic properties of the arteries are essential for blood flow. An elastic body is one that returns to its original. Only two material parameters need to be experimentally determined.
Forces, elasticity, stress, strain and youngs modulus handout pdf. Displacementsstrain to stressmomentum formulation in linear elasticity i was going through this paper page 2 where they describe a duality between a fracton theory and linear elasticity in 2. Elasticity is the property of solid materials to return to their original shape and size after the forces deforming them have been removed. Tensors are referred to by their rank which is a description of the tensors dimension. Elasticity, stress, strain, and fracture boundless physics. Elasticity 3 uniform compression demonstration if the forces are applied uniformly in all directions, we have a deformation typified by that produced by a uniform hydrostatic pressure. It explains how to calculate the stress and strain of materials when an. Eventually a large enough stress to the material will cause it to break or fracture.
A second rank tensor looks like a typical square matrix. Science class 11 physics india mechanical properties of solids stress, strain, and modulus of elasticity stress, strain, and modulus of elasticity elastic and non elastic materials. Science physics elasticity numerical problems on stress, strain, and youngs modulus in this article, we shall study concept application and numerical problems on longitudinal stress, longitudinal strain, youngs modulus of elasticity. To a greater or lesser extent, most solid materials exhibit elastic behaviour, but there. Its unit is nm 2 or pascal and its dimensional formula is ml 1 t 2. The cauchy strain or engineering strain is expressed as the ratio of total deformation to the initial dimension of the material body in which the forces are being applied. It is the ability of returning its original shape after removing the applied stress. A zero rank tensor is a scalar, a first rank tensor is a vector.
After a region k to l of partial elastic behaviour, plastic flow continued from l to m. Stress, strain, thermal conductivity, magnetic susceptibility and electrical permittivity are all. Forces, elasticity, stress, strain and youngs modulus. Note that this stress strain curve is nonlinear, since the slope of the line changes in different regions. In response to a small, rapidly applied and removed strain, these fluids may deform and then return to their original shape. This can be easily shown by substituting for k fx into the equation for e. Elasticity if an external force is applied to a material, it causes deformation in molecular structure of that material.
If your donation is for a physics course, please allocate your donation to the department of physics fund. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Introduction to elasticity theory stressstrain relationships in all the questions here tension is considered positive and compression is considered negative. Pa this longitudinal modulus of elasticity is called youngs modulus and is denoted by the symbol. Explain hookes law using graphical representation between deformation and applied force. Recall hookes law first stated formally by robert hooke in the true theory of elasticity or springiness 1676 ut tensio, sic vis. L is proportional to the force applied at least for small deformations. Deformation in continuum mechanics is the transformation of a body from a reference configuration to a current configuration. Nov 04, 2017 this physics video tutorial provides practice problems associated with the elastic modulus and shear modulus of materials. Discuss the three types of deformations such as changes in length, sideways shear and changes in volume. Thermal stress and strain,poissons ratio jeeneet duration. Science class 11 physics india mechanical properties of solids stress, strain, and modulus of elasticity. Mechanical deformation puts energy into a material.
A twisted rope has a relation between normal stress, along the rope, and twist of the rope. By removing this force, material turns its original shapes. When thinking about elasticity, think about a coiled metal spring or a rubber band. Sep 24, 2017 apr 21, 2020 elasticity, stress and strain and stressstrain curve, class 11, physics edurev notes is made by best teachers of class 11.
Mar 29, 2020 figure shows a stress strain relationship for a human tendon. Stress, strain, and elastic modulus part 1 physics. Technically, elasticity is the property of a material to recover its strain after removal of stress. Microsoft powerpoint chapter15 compatibility mode author. Lecture 7 elasticity 1 physics 460 f 2006 lect 7 1 elasticity stress and strain in crystals kittel ch 3 physics 460 f 2006 lect 7 2 elastic behavior is the fundamental distinction between solids and liquids similartity. Strain energy elastic strain energy, u energy spent by the external forces in deforming an elastic body du0. The first two sets of equations are universal independent of the. Elasticity, stress and strain and stressstrain curve, class. On a stress strain graph the youngs modulus is constant for the portion of the graph where hookes law applies. On the other hand, a small elastic modulus means that stress produces large strain and noticeable deformation. In this video lets explore what these are and why we define them. If the deformation, or strain the ratio of the change in length to the initial length, is. Physics 3 summer 1989 lab 7 elasticity theory all materials deform to some extent when subjected to a stress a force per unit area.
The coefficient that relates a particular type of stress to the strain that results is called an elastic modulus plural, moduli. Elastic materials have internal forces which restore the size and shape of the object when the stress is removed. Elasticity, stress and strain and stressstrain curve. This physics video tutorial provides practice problems associated with the elastic modulus and shear modulus of materials.
Stressstrain curves are useful to understand the tensile strength of a given material. Modeling elasticity the elastic regime is characterized by a linear relationship between stress and strain, denoted linear elasticity. Pdf an overview of stressstrain analysis for elasticity equations. Hdpe shows a relatively high modulus of elasticity combined with high impact toughness vasile and seymour 1993 resulting form a twophase morphology that is composed by a hard crystalline and a soft amorphous phase. For example, a stress on a rubber band produces larger strain deformation than the same. Elasticity understanding elasticity from stress strain. Objects that are very elastic like rubber have high elasticity and stretch easily. Hookes law states that the extensionx of a spiral spring. Tensors, stress, strain, elasticity mineral physics. Elasticity solved examplesproblems physicscatalyst.
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